Apparatus for heating capsule forming pins

ABSTRACT

Heating means for medicinal capsule forming pins and comprises a tray containing heated generally spherical particles, means to heat the particles, and means to raise the tray to impress the particles around the forming pin whereby they are rapidly heated. The tray is retracted before the pins are moved to the pin dipping position of the capsule forming machine.

United States Patent [191 Chisholm 1 Oct. 15, 1974 1 APPARATUS FOR HEATING CAPSULE FORMING PINS [75] Inventor: Douglas S. Chisholm, Midland,

Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

22 Filed: Feb. 1, 1974 21 Appl. No: 438,912

[52] US. Cl 219/385, 165/104, 219/388, 219/439, 219/521, 219/530, 219/540,

[51] Int. Cl. F27d 11/00 [58] Field of Search 219/385, 388, 432, 439, 219/521, 523, 530, 540; 425/96, 174, 274,

[56] References Cited UNITED STATES PATENTS 1,787,777 l/l931 Colton 425/96 1,809,510 6/1931 Churchill 219/385 X 2,262,506 11/1941 Levandowski 219/385 X 2,562,821 7/1951 Rothweiler 219/530 X 2,671,245 3/1954 Kath 425/96 X 2,988,624 6/1961 lseli-B0ssardt,.. 219/540 X 3,147,799 9/1964 Chadburn et a1 165/86 3,390,717 7/1968 Townsend 165/86 X 3,515,855 6/1970 Mix, Jr 165/104 X 3,609,296 9/1971 Blair 165/107 X FOREIGN PATENTS OR APPLICATIONS 569,390 5/1945 Great Britain 165/104 Primary ExaminerVolodymyr V. Mayewsky Attorney, Agent, or Firm-Earl D. Ayers [57] ABSTRACT Heating means for medicinal capsule forming pins and comprises a tray containing heated generally spherical particles, means to heat the particles, and means to raise the tray to impress the particles around the forming pin whereby they are rapidly heated. The tray is retracted before the pins are moved to the pin dipping position of the capsule forming machine.

10 Claims, 5 Drawing Figures PATENIEBDEI 1 5 m4 can fro l/er Timer and W 5 o a 0 1 E O a a D :1 5 on 0 i u 0 C a o a I 26 o b h o z o u o a l 0 our; r n O o o o o f i M o a g o 00 o o D 0 o be 0 O 0 on $3 000, g ooo oaooo o APPARATUS FOR HEATING CAPSULE FORMING PINS BACKGROUND OF THE INVENTION This invention relates to means for preheating capsule forming pins before their immersion in the capsule forming material, and particularly to such means wherein heated particulate material is used to contact the capsule forming pins.

In the past, medicinal capsules have generally been composed of gelatin and no need existed for preheating the capsule forming pins.

At the present time, gelatin materials are sometimes in short supply and substitute capsule materials are given serious consideration.

Capsules made of methyl cellulose, for example, are attractive alternatives to gelatin capsules. However, the material runs" on the capsule forming pins unless they are preheated to a predetermined temperature.

Almost all capsule making machines are so called Colton machines or are variations of the Colton machine, U.S. Pat. No. l,787,777 issued Jan. 6, 1931 for Capsule Machines.

Thus, because of the huge investment in Colton capsule machines, any alternate capsule material should be either compatible for use with the Colton machine, or the machine be adaptable for use with the alternate capsule material.

Various means have been proposed to preheat capsule forming pins just prior to their being dipped into the capsule forming material.

However, some such means overheated the adjacent parts of the capsule making machine, other means heated the various forming pins unevenly, while others tended to biologically contaminate the pins.

Other means were simply not compatible for use with Colton capsule machines or the like wherein such a preheating means must fit in a space restricted part of the machine and wherein the pins were in a location where preheating could occur for only about l5 seconds.

OBJECTS OF THE INVENTION STATEMENT OF INVENTION In accordance with this invention there is provided apparatus for preheating capsule forming pins in a capsule making machine, said apparatus including a traylike member having generally spherical particulate heat transfer material therein, means for heating said heat transfer material, and means for bringing said heat transfer material into contact with and for removing said material from said contact at predetermined time intervals.

BRIEF DESCRIPTION OF THE DRAWING The invention, as well as additional objects and advantages thereof, will best be understood when the following detailed description is read in connection with the accompanying drawing, in which:

FIG. 1 is a fragmentary view of a Colton type capsule making machine showing apparatus in accordance with this invention in operative relationship with said ma-' DETAILED DESCRIPTION OF THE DRAWING Referring to the drawing there is shown in FIG. 1 a fragmentary view of one end of a Colton capsule making machine of the type disclosed in U.S. Pat. 1,787,777 issued Jan. 6, 1931.

In this type of capsule making machine bars 12 each containing a plurality (thirty is common) of capsule (part) forming pins 14 are collected in groups of five bars and are progressively moved to a position over the tank 16 which contains heated fluid 18 between the inner and outer walls of the tank and which contains liquid methyl cellulose 20 or the like in the tank reservorr.

Movement of the groups of five bars 12 is controlled by a carrier block 22 and pawls (only one pawl, 24, is shown in FIG. I). When the bars 12 are in the last position before going into the dipping position above the capsule forming material 20, they are stationary for about fifteen seconds.

A tray-like member 26 is disposed below the group of five bars 12 which are in the last position before being positioned over the tank 20.

Ther tray is supported on a raising and/or lowering mechanism, such as a pneumatic cylinder 28 supported on a base 30. Lines or conduits 32, 34 are coupled between the cylinder 28 and a timer-controller assembly 36. Thus, movement of fluid through the lines 32, 34 at predetermined times controls the upward and downward movement of the tray-like member 26. The timer and controller is, of course, programmed to coordinate movement of the tray-like member 26 with the cyclic operational rate of the capsule making machine.

Referring now to FIGS. 2-5, as well as to FIG. 1, the tray-like member 26 is so dimensioned that the pins 14 of a group of five bars 12 all fit within the length and width of the member 26.

The depth of the member 26 is such that, with the member 26 at least partially filled with generally spherical particles of heat transfer material 38 such as 400 series chrome steel, for example, the pins 14 of the bars 12 extend into the heat transfer material 38 for at least an inch when the member 26 is in its upper position.

Heating means 40 are provided in the heat transfer material 38. Electrical resistance heating means are illustrated and, as shown by the external plug in terminals 42 in FIG. 2, may consist of strip or coil resistance elements extending from end to end of the pan-like member 26. Alternative heating means may be used. Steam lines could be disposed in the heat transfer material, hot gas could be circulated in the tray-like member 26 or the member 26 could be heated by heat from a gas combustion unit. Electrical resistance heaters, however, are practical and convenient for most uses of this invention.

Power connections to the electrical resistance heaters 40 are shown by the short leads 44, 42 of FIG. 2.

It is possible that occasionally one of the heat transfer elements (a sphere, as shown in FIG. 4, for example) will adhere to one of the pins 14 as the pins and heat transfer material are separated. If such should be a problem, a cover plate 46 made of magnetic material and having an array of bores 48 is attached to the top of the member 26. The array of bores 48 is such that the pins 14 each extend through a bore 46.

When the cover plate 46 is magnetized, any particle 38 which tends to adhere to a pin 14 (usually nonmagnetic stainless steel), it is attracted to and moves to the cover plate, leaving the pin 14 clear of particles.

Alternatively, the cover 46 may be made of nonmagnetic material (a thermal insulator, for example) and magnetic material in strip or other form disposed on the cover or near by adjacent to the path followed by the pins 14.

OPERATION in operation, when an array of bars 12 is in the rest position, indicated by the arrow 50, adjacent to the array of bars and pins in the elevator part 52 by which they are dipped into and removed from the molten capsule material 20 by means of rack 54 and segment 56, the tray-like member is moved upwardly so that the heat transfer material 38 contacts the pins 14 over a substantial part of their length. The heating means in the member 26 maintains a temperature of approximately two hundred degrees Centigrade in the material 38, recognizing there will be heat loss and dropping temperature locally when unheated pins 14 are contacted by the material 38.

The pins 14 (or at least the methocel receiving parts are raised from a temperature of about 20 Centigrade to about 60 Centigrade within the approximately 15 seconds the pins are in this static position. Before lateral movement of the pins 14, the member 26 is retracted until it is entirely out of alignment with lateral movement of the pins.

Then, after the group of bars ahead of the preheated bars is dipped, drawn out of the capsule material, and advanced, the group of preheated pins 14 are advanced to the elevator 52 and are, while the pins 14 are still heated to about 60 Centigrade, dipped into the capsule material 20.

The dipping of the preheated pins by virtue of thermal gelation prevents excess running of the methyl cellulose type capsule material, resulting in more uniform capsule configuration than is practical to achieve without preheating of the pins.

The size of the particulated heat transfer material should be such that the material in the member 26 acts pretty much like a fluid in settling around the pins 14. Suggested sizes are from about 0.006 inch diameter to about 0.06 inch in diameter, with spherical particles of about 0.032 inch diameter proving easy to use.

The generally spherical particles 38a may be made of 400 series chrome steel or of other metal which will not oxidize at the temperature in the tray-like member 26 (commonly about 200 Centigrade). The particles 38a need not be truly spherical, but should at least be rounded to the extent 1) that the polished stainless steel pins 14 are not excessively abraded, and 2) that the fluid-like movement of the particles when the pins are contacted is not substantially impeded.

Other materials may be used as heat transfer materials. Polytetrafluoroethylene, in spherical form, for example, would be operable in that it could withstand the encountered temperatures and would not abrade or contaminate the pins 14.

If a cover plate 46 is used and the clearance between the apertures 48 and the forming pins 15 extending through them is less than the diameter of the individual pieces of particulate heat transfer material, then no adhering heat transfer material would escape the container 26. Such a setup involves fairly close registry of movement between the container 26 and forming pins 15, but such registry is readily attainable with proper design of the equipment.

What is claimed is:

1. Apparatus for preheating capsule forming pins in a capsule forming machine in which successive arrays of forming pins are advanced from position to position including a dipping position and a holding position immediately preceding said dipping position, comprising 2. Apparatus in accordance with claim 1 wherein said heat transfer material has a maximum cross-sectional dimension of between 0.006 inch and about 0.06 inch.

3. Apparatus in accordance with claim 1 wherein said heat transfer material is a metal.

4. Apparatus in accordance with claim 1 wherein said means for heating comprises electrical heating means embedded in said heat transfer means.

5. Apparatus in accordance with claim 1 wherein said means for cyclically moving comprises a raising and lowering device coupled to timer-controller means.

6. Apparatus in accordance with claim 1 wherein said contaner has a cover containing aperture in alignment with said forming pins.

7. Apparatus in accordance with claim 1 wherein said heat transfer means are made of 400 series chrome steel.

8. Apparatus in accordance with claim 1 wherein magnetic means are provided adjacent to the forming pins whereby magnetic material adhering to said forming pins is removed therefrom.

9. Apparatus in accordance with claim 6 wherein there is an aperture for each pin, and the clearance between each pin and the aperture through which it extends is less than the minimum cross-sectional dimension of an individual piece of heat transfer material.

10. Apparatus in accordance with claim 1 wherein said heat transfer material comprises aluminum. 

1. Apparatus for preheating capsule forming pins in a capsule forming machine in which successive arrays of forming pins are advanced from position to position including a dipping position and a holding position immediately precedinG said dipping position, comprising a thermally insulating container a mass of generally spheroidal particulate heat transfer material, being disposed in said container, means in said container for heating said heat transfer material, and means for cyclically moving said container of heat transfer material with respect to said array of forming pins in said holding position whereby said heat transfer material first surrounds said pins along a substantial part of their length and then is withdrawn with respect to said pins.
 2. Apparatus in accordance with claim 1 wherein said heat transfer material has a maximum cross-sectional dimension of between 0.006 inch and about 0.06 inch.
 3. Apparatus in accordance with claim 1 wherein said heat transfer material is a metal.
 4. Apparatus in accordance with claim 1 wherein said means for heating comprises electrical heating means embedded in said heat transfer means.
 5. Apparatus in accordance with claim 1 wherein said means for cyclically moving comprises a raising and lowering device coupled to timer-controller means.
 6. Apparatus in accordance with claim 1 wherein said contaner has a cover containing aperture in alignment with said forming pins.
 7. Apparatus in accordance with claim 1 wherein said heat transfer means are made of 400 series chrome steel.
 8. Apparatus in accordance with claim 1 wherein magnetic means are provided adjacent to the forming pins whereby magnetic material adhering to said forming pins is removed therefrom.
 9. Apparatus in accordance with claim 6 wherein there is an aperture for each pin, and the clearance between each pin and the aperture through which it extends is less than the minimum cross-sectional dimension of an individual piece of heat transfer material.
 10. Apparatus in accordance with claim 1 wherein said heat transfer material comprises aluminum. 